Recently, there is an increasing necessity of multimedia services, such as e-mail service, image communication service, and Internet service, as well as voice communication service, which are provided through a wireless communication system. In this respect, it is general that a plurality of services are simultaneously transmitted through a downlink channel or an uplink channel.
When transmitting a plurality of services by multiplexing them, it is important how many radio resources are allocated in accordance with which basis so as to transmit each service. In general, priority of each service is determined depending on service types, billing system, etc., and radio resources are allocated depending on the determined priority.
The method for allocating radio resources depending on priority has a problem in that quality of service (QoS) may be disregarded. For example, when a plurality of services having different priorities are transmitted, if data of a service having high priority occur continuously, radio resources will continuously be allocated to the service having high priority depending on priority. In this case, a problem occurs in that radio resources are not allocated to a service having low priority for a long time, whereby service quality required for the corresponding service within the minimum range may not be obtained.
As described above, the status where data of a service cannot be transmitted due to transmission of another service having higher priority is called ‘starvation.’ The starvation acts to remarkably deteriorate service quality of a specific service. For example, in case of a real time service such as audio streaming, data should be transmitted continuously at a given quantity. However, if starvation occurs due to priority, packets which have not been transmitted for a long time are not required any longer and thus are discarded. As a result, a problem occurs in that service quality is deteriorated.